Method and apparatus for ejecting viscous material



G. J. GODDARD ETAL METHOD AND APPARATUS FOR EJECTING VISCOUS MATERIAL Filed 1965 FIG. I

NT0R5 GEORGE J. GODDARD RRY J. EVANS FRANCIS M. ALPISER TORNEY container to one or more rocket motor casings.

United States Patent This invention relates to a method and apparatus for ejecting a viscous material and more particularly to a method and apparatus for ejecting a viscous material from a container which precludes the possibility of air being entrapped with said material as it is ejected.

In many manufacturing operations, it is advantageous to place a viscous material in a reservoir and thereafter transfer the material, under pressure, from this reservoir to one or more containers which are to be filled therewith. For example, in the manufacture of solid propellant rockets, liquid propellant of high viscosity is often stored in a large cylindrical container provided with a close-fitting piston, or float, as it is termed in the art of propellant casting, by means of which the propellant is forced through one or more outlets leading from the With the conventional methods andapparatus heretofore employed in such propellant transfer operations, air is often entrapped with the propellant in the transfer container and ejected with it to a rocket motor casing, producing voids in the charge of said motor which can cause the motor to be scrapped or to explode if it is actually fired. This entrapment of air is most likely to occur when the propellant material in a transfer container reaches a low level therein and air trapped between the float and propellant reaches the outlet of the storage container with the last part of the stored propellant and escapes to the rocket motor casing being filled.

Therefore, it is an object of this invention to provide a method and apparatus for ejecting a viscous material from a storage container which prevents the escape of air from said container with said material.

It is another object of this invention to provide an effective and economical method for sealing the outlet of a storage container when substantially all of a viscous material held in said container has been ejected through said outlet.

-It is an additional object of this invention to provide a material ejecting apparatus, the outlet of which is automatically sealed when substantially all of a viscous material held in said apparatus has been ejected therefrom.

The method and apparatus by which the foregoing objects are accomplished will readily be understood from the following description, considered in conjunction with the accompanying drawings, in which:

FIGURE 1 is a partially sectional and partially diagrammatic view illustrating apparatus which constitutes a preferred embodiment of the invention and which can be used to carry out the steps of a preferred method of practicing the invention;

FIGURE 2 is a partially sectional and partially diagrammatic view illustrating a second apparatus which can be used to carry out the steps of a preferred method of practicing the invention; and

FIGURE 3 is a partially sectional and partially diagrammatical view illustrating a third apparatus which can also be used to carry out the steps of a preferred method of practicing the invention.

The preferred apparatus embodiment of the invention illustrated in FIG. 1 comprises a cylindrical container which is provided at one end with an integral end closure ice 12 having an outlet 14 connected thereto. A valve 16 or other suitable flow control means is connected between outlet 14 and a feed pipe 18 through which a viscous material 20 stored in container 10 can be passed to one or more containers to be filled with said material. A closure member 22 is detachably secured by means of a plurality of bolts 24 and nuts 26 to a flange 28 that projects from the upper end of container 10, this closure member having two apertures 30, 32 formed therein. A bushing 34 is fixedly disposed within aparture 30, and a first tube 36 is fixedly disposed within aperture 32, said tube 36 being connected to a hose 37 that is in turn connected to a pump 38 or other suitable means for injecting air into the interior of container 10. A gasket 40 is disposed between flange 28 and closure member 22 to facilitate sealing the interior of container 10.

Disposed against the upper surface of the material 20 stored in container 10 is a disk-shaped sheet 42 formed of a suitable flexible material. In the preferred apparatus embodiment of the invention herein described, which is being used for casting propellant in rocket motor casings, sheet 42 has a diameter of about 3 feet and comprises a plurality of reinforced neoprene sheets sandwiched between face sheets of neoprene that are not reinforced, the overall thickness of the composite sheet being 0.6 inch. The diameter of sheet 42 is preferably slightly less than the inside diameter of container 10, thus facilitating the placement of said sheet against the surface of material 20 without bringing a portion of its edge into contact with the wall of said container and thereby forming folds or corrugations at said edge which could prevent the establishment of an air-free area of contact between the entire lower surface of the sheet and the upper surface of material 20, which is hereinafter described as one of the steps of carrying out the preferred method of practicing the invention.

In ejecting material 20 from container 10, downward pressure is exerted against sheet 42 by means of a piston, generally designated by the number 44, which comprises a first disk-shaped end portion 46 and a second circumferentially-extending skirt 48 integral with said end portion and disposed perpendicular thereto. Thus, when the illustrated embodiment of the invention is in use, sheet 42 is adjacent both the upper surface of material 20 and the lower, or interior, surface of piston 44. The periphery of skirt 48 of piston 44 is in close-fitting, slidable contact with the interior wall of container 10, and thus 'seals the space in container 10 between said piston and sheet 42. Piston 44 includes an aperture 50 in which a second tube 52 is fixedly positioned, this tube extending through bushing 34 in closure member 22 and being in slidable contact with the inner wall of said bushing. The other end of tube 52 is connected to a vacuum pump 54 by means of a detachable hose 56.

After material 20 has been placed in container 10, sheet 42 is preferably placed against the upper surface of said material in the manner described immediately hereinafter. Sheet 42 is first folded along a line that passes through the center the eof, thus forming a linear fold edge on said sheet. This linear fold edge of sheet 42 is then brought into contact with the surface of material 20, with care being taken to position the fold edge so that when sheet 42 is unfolded and pressed against the surface of material 20, the gap between the sheet and the wall of container 10 will be uniform. Thereafter the air-free area of contact between sheet 42 and material 20 is increased by lowering the two semicircular sections of sheet 42 (formed when said sheet is folded) against the surface of material 20 outwardly from said fold edge, with care being taken that sheet 42 is pressed firmly against material 20 to preclude the entrapment of air thereunder. In other words, the boundary of the air-free area of contact between sheet 42 and the surface of material 20 is extended without interruption over the entire lower surface of said sheet after initial contact between sheet 42 and material 20 is made. If the surface of material 20 is uneven, it may be advantageous to knead sheet 42 as it is brought into contact with material 20 to insure that no air pockets are formed as sheet 42 is placed against material 20. Proper contact between sheet 42 and material 20 can also be achieved by contacting any particular portion of said sheet against said material initilly and then increasing the area of contact therebetween as described above.

After sheet 42 has been placed upon the upper surface of material 20 as described above, piston 44 is inserted in the upper end of container 10 and positioned adjacent said sheet, trapped air being vented from the interior of said container through tube 52 as the piston is lowered therein. Closure member 22 is next secured to the upper end of container 10, tube 52 being inserted in bushing 34 as said closure member is lowered into position. Hose 56 is next attached to the projecting end of said tube, and pump 54 is operated to remove air from the space between piston 44 and sheet 42. When material 20 is to be ejected from container 10, valve 16 is opened and pump 38 operated to inject air under pressure into the space between piston 44 and closure member 22. Air pressure exerted against end portion 46 of piston 44 forces the piston downwardly in container 10 and ejects material 20 through outlet 14. When piston 44 has been forced downwardly in container 10 to a point which brings sheet 42 into contact with the upper surface of the end closure 12 thereof, said sheet seals outlet 14 and prevents air which may leak into the space between said sheet and piston 44 from passing out of container 10 with the last portion of the material 20 ejected therefrom. Valve 16 is then closed and container 10 reloaded by means of the steps set out above. Thus, the principal object of the invention, namely, preventing escape of air from a storage reservoir through a feed line connected thereto, is accomplished by means of the above-described preferred apparatus embodiment of the invention.

The second apparatus embodiment of the invention illustrated in FIGURE 2 has a closure member 22 which includes only one aperture 32', in which an air supply tube 36' is fixedly positioned. A tube 52, provided with a valve 60,is connected to a piston 44 of this embodiment, this tube being in communication with the space between said piston and a flexible sheet 42' positioned against the upper surface of material 20 he;d in container 10. In this second embodiment, the outlet 14 projects slightly above the upper surface of end closure 12, whereas in the above-described preferred embodiment, the upper end of outlet 14 is even with the upper surface of end closure 12. Otherwise the components of the second embodiment are identical to those of the above-described preferred apparatus embodiment of the invention. In ejecting material 28 from the container 10, piston 44' is inserted into said container (after it has been filled with said material 20' and sheet 42 has been placed on the surface thereof as described above in the description of the preferred embodiment of the invention) and air is then removed from the space between piston 44 and sheet 42 by connecting tube 52 to a vacuum pump. Valve 60 is closed, the vacuum pump disconnected from tube 52, and closure member 22 secured to the upper end of container 10. By means of pump 38 air is then injected into the upper portion of container 10 to force piston 44 downwardly and thereby eject the material 20 through outlet 14. In the operation of the second embodiment, sheet 42 contacts and seals the upper end of outlet 14' when piston 44 reaches a point near end closure 12. It will thus be .seen that the second embodiment can also be used to carry out the steps of the preferred method of practicing which has been described above.

In a third apparatus embodiment of the invention, one end of a tube 52" is connected to a piston 44" and the other end of this tube is connected to a vacuum pump 54" by means of a flexible hose 56". One end of a drive shaft 62 is also connected to piston 44", the other end of said drive shaft being connected to means (not shown) adapted to move said shaft longitudinally of container 10". It will be obvious that the steps required to eject material 20 from container 10" correspond to those stated above in the description of the other embodiments of the invention.

Although the invention has been described in detail with reference to specific embodiments of the invention, it is to be understood that the same are intended for illustration and example only and not for the purpose of limitation, the scope of the invention being limited only by the terms of the appended claims.

What is claimed is:

1. A method of ejecting a viscous material comprising the steps of:

placing said material in a container having at one end thereof an end closure and at least one outlet connected to said end closure;

placing a flexible sheet against the surface of said material facing the other end of said container so as to establish an air-free area of contact between said sheet and said material;

placing a piston within said container adjacent said sheet;

removing air from the space between said piston and said sheet, and;

moving said piston toward said outlet to eject said material therethrough and to subsequently seal said outlet with said sheet.

2. A method of ejecting a viscou material comprising the steps of:

placing said material in a container having at one end thereof an end closure and at least one outlet connected to said end closure; contacting a portion of a flexible sheet with the surface of said material facing the other end of said container so as to establish an air-free area of contact between said sheet and said material, and thereafter contacting the remainder of said sheet with said surface so that said air-free area of contact therebetween is increased;

placing a piston within said container adjacent said sheet;

removing air from the space between said piston and said sheet;

moving said piston toward said outlet to eject said material therethrough and to subsequently seal said outlet with said sheet.

3. A method of ejecting a viscous material comprising the steps of placing said material in a container having at one end thereof an end closure and at least one outlet connected to said end closure;

contacting a portion of a flexible sheet with the surface of said material facing the other end of said container so as to establish an air-free area of contact between said sheet and said material, and thereafter contacting the remainder of said sheet with said surface sO that the boundary of said air-free area of contact therebetween is extended without interruption over the entire area of said sheet;

placing a piston within said container adjacent said sheet;

removing air from the space between said piston and said sheet; and

moving said piston toward said outlet to eject said material therethrough and to subsequently seal said outlet with said sheet.

4. A method of ejecting a viscous material comprising the steps of:

placing said material in a container having at one end thereof an end closure and at least one outlet connected to said end closure;

folding a flexible sheet along a medial line thereof to form a linear fold edge thereon;

contacting said fold edge of said sheet with the surface of said material facing the other end of said container, and thereafter contacting the remainder of said sheet with said surface outwardly from said fold edge;

placing a piston within said container adjacent said sheet;

removing air from the space between said piston and said sheet;

moving said piston toward said outlet to eject said material therethrough and to subsequently seal said outlet With said sheet.

5. Apparatus for ejecting a viscous material comprisa container having at one end thereof an end closure and at least one outlet connected to said end closure;

flow control means connected to said outlet;

a piston disposed within said container remote from said outlet;

a flexible sheet disposed within said container adjacent the interior surface of said piston;

means for removing air from the space between said piston and said sheet; and

means for moving said piston toward said outlet.

6. Apparatus as defined in claim 5 wherein the edge of said sheet is spaced from the wall of said container.

7. Apparatus for ejecting a viscous material comprisa cylindrical container having at one end thereof an end closure and at least one outlet connected .to said end closure;

flow control means connected to said outlet;

a closure member secured to the other end of said container, said closure member detachable from said container and having first and second apertures therein;

a bushing fixedly disposed in said first aperture;

a first tube fixedly disposed in said second aperture;

a piston disposed within said container between said closure member and said outlet, said piston having a disk-shaped end portion and a circumferentiallyextending skirt engaging the wall of said container, said end portion having an aperture therein;

a flexible sheet disposed within said container adjacent the interior surface of said piston;

a second tube having one end fixedly disposed in said aperture in said end portion of said piston, said second tube extending through said bushing in said closure member and being in slidable contact therewith;

means connected to said second tube for removing air from the space between said piston and said sheet; and

means connected to said first tube for injecting air into the space in said container between said piston and said closure member, so that said piston is moved toward said outlet and material disposed within said container between said sheet and said outlet is ejected through said outlet, and said sheet is subsequently moved into contact with said end closure and seals said outlet.

8. Apparatus for ejecting a viscous material comprising:

a cylindrical container having at one end thereof an end closure and at least one outlet connected to said end closure, said outlet projecting on both sides of said end closure;

flow control means connected to said outlet;

a piston disposed within said container remote from said outlet, said piston having a disk-shaped end portion and a flexible circumferentially-extending skirt integral with said end portion, said skirt being in slidable contact with the wall of said container;

a flexible sheet disposed within said container adjacent the interior surface of said piston;

a tube fixedly connected to said end portion of said piston and in communication with the space between said piston and said sheet, said tube including flow control means operably connected therewith;

means detachably connected to said tube for removing air from the space between said piston and said sheet;

a closure member detachably secured to the end of said container opposite said outlet; and

means connected to said closure member for injecting air into the space in said container between said piston and said closure member, so that said piston i moved toward said outlet and material disposed within said container between said sheet and said outlet is ejected through said outlet, and said sheet is subsequently moved into sealing contact with said outlet.

9. Apparatus for ejecting a viscous material comprisa cylindrical container having at one end thereof an end closure and at least one outlet connected to said end closure;

flow control means connected to said outlet;

a piston disposed within said container remote from said outlet;

a flexible sheet disposed within said container adjacent the interior surface of said piston;

a tube fixedly connected to said piston and in communication with the space between said piston and said sheet;

means connected to said tube for removing air from said space between said piston and said sheet;

a drive shaft connected to the side of said piston remote from said sheet; and

means for moving said shaft longitudinally of said container, so that said piston is moved toward said outlet and material disposed within said container between said sheet and said outlet is ejected through said outlet, and said sheet is subsequently moved into contact with said end closure and seals said outlet.

References Cited by the Examiner UNITED STATES PATENTS 2,221,763 11/1940 Ginter 222259 X 2,630,248 3/1953 Hinz 222-259 X 2,997,215 8/1961 Chinchole 222-261 SAMUEL F. COLEMAN, Primary Examiner. 

1. A METHOD OF EJECTING A VISCOUS MATERIAL COMPRISING THE STEPS OF: PLACING SAID MATERIAL IN A CONTAINER HAVING AT ONE END THEREOF AN END CLOSURE AND AT LEAST ONE OUTLET CONNECTED TO SAID END CLOSURE; PLACING A FLEXIBLE SHEET AGAINST THE SURFACE OF SAID MATERIAL FACING THE OTHER END OF SAID CONTAINER SO AS TO ESTABLISH AN AIR-FREE AREA OF CONTACT BETWEEN SAID SHEET AND SAID MATERIAL; PLACING A PISTON WITHIN SAID CONTAINER ADJACENT SAID SHEET; REMOVING AIR FROM THE SPACE BETWEEN SAID PISTON AND SAID SHEET, AND; MOVING SAID PISTON TOWARD SAID OUTLET TO EJECT SAID MATERIAL THERETHROUGH AND TO SUBSEQUENTLY SEAL SAID OUTLET WITH SAID SHEET. 